Door latch devices for vehicles include those, each in which an interlocking unit assembly is integrated with an operating unit assembly; the interlocking unit assembly including a body fixed to a door and made of synthetic resin, a latch accommodated in the body and engageable with a vehicle body side striker, and an interlocking mechanism, such as a pole engageable with the latch; and the operating unit assembly including a casing fixed to a reverse side of the body and made of synthetic resin, and an operating mechanism, which is installed in the casing, and which is able to switch over the door between a locked state and an unlocked state by the interlocking mechanism being operated (see, for example, Patent Literatures 1 and 2).
Further, some door latch devices include a half closed door detection switch that detects a half closed state of the door by detecting the position of the latch.
Furthermore, some door latch devices include a switch plate, on which electrically operating parts, such as a switch and a motor installed in the operating unit assembly, are mounted, and which is integrally installed with the casing of the operating unit assembly.